Open almost any book on grammar or writing skills, and you'll come across the advice "Use the active voice in preference to the passive voice".

Also, if you use Microsoft Word, you'll often get similar advice from its grammar checker.

Free of all the grammatical jargon, what does this mean?

Well, sentences written in the ACTIVE voice have the following structure:

                     DO-ER  ACTION  RECEIVER

For example:

                     John wrote the report.

                     We misplaced your correspondence.

                     The council reserved its decision.

                     The ratepayer thanked him.

As you can see, sentences written in the active voice all start with the do-er of the action.

Sentences written in the PASSIVE voice, though, start with the receiver of the action:

                     RECEIVER  ACTION  BY-WHOM

For example:

                     The report was written by John.

                     Your correspondence was misplaced by us.

                     The decision was reserved by the Council.

                     He was thanked by the ratepayer.

Okay, so we've made a distinction between the two. This brings us back to the traditional advice that it is preferable to write in the active voice rather than the passive voice.

Why?

The reason for this is that the active voice tends to sound simpler and more direct. Also, it often requires fewer words.

For example:

                     The dog bit him.                                  [Active]

                     He was bitten by the dog.                    [Passive]

                     We will send your goods within 14 days.              [Active]

                     Your goods will be sent by us within 14 days.       [Passive]

Personally, I don't feel that the world is going to end if you write a few sentences in the passive voice now and then. Nonetheless, using the active voice in the majority of cases will improve your writing by making it simpler and more direct.

The passive voice does have one "advantage" though: it allows us leave out the do-er. Consider this alternative structure for passive sentences:

                     RECEIVER  ACTION

For example:

                     The report was written.                                 [By whom?]

                     Your correspondence was misplaced.            [By whom?]

                     The decision was reserved.                           [By whom?]

                     He was thanked.                                          [By whom?]

By leaving out the do-er, the passive voice allows us to hide responsibility. It is thus much loved in government reports.  :-)

When we write in the active voice, though, we are forced to identify the do-er, and this eliminates a certain amount of evasion.